1901 | GAMETOGENESIS AND FERTILIZATION IN ALBUGO gt 
ALBUGO CANDIDA. 
The result of the study of A. 7ragopogonis suggested that the 
great variation in mode of fertilization seen in this genus might 
be explained in a way hitherto unsuspected. I have studied A. 
candida, therefore, comparing it stage for stage with the other 
species referred to in this paper. My observations essentially 
agree with those of Wager (1896), which were confirmed and 
extended by the research of Davis (1900). I have here only to 
present some further details, to make certain homologies clear, 
and in no radical way to alter the statements of these two 
writers, 
The initial step in development consists of a differentiation 
of the ooplasm in the center of the oogonium, the nuclei in the 
meantime undergoing mitosis. One stage in this process is 
beautifully figured by Davis (1900, fig. 2), and a stage slightly 
older is herewith presented (fig. rg). It should be noted in 
these figures that the ooplasm is much more vacuolate than in 
the other known species ( figs. 3, 74, 28). Particularly in the 
figure by Davis will it be seen that the ooplasm is separated 
from the periplasm by a rather broad irregular zone of very dense 
cytoplasm. 
The conditions presented even in this early stage of oogene- 
Sis are markedly different from those of the other species. 
There is apparently no preliminary aggregation of cytoplasm 
into masses, but rather a simultaneous movement from the 
oogonial wall toward the center, leaving behind only slender 
threads of cytoplasm. It appears as though this movement 
occurs as a wave starting at the oogonial wall and moving so as 
to crowd the cytoplasm into the dense zone represented in the 
figures. When this condition obtains, the nuclei are approxi- 
mately in metaphase, and it is clear that this represents the first 
nuclear division. Nuclei in metaphase and late anaphase may 
be seen in the same oogonium, but it is not probable that one 
nucleus undergoes more divisions than another, since the nuclei 
simultaneously pass through the stages of early prophase. 
t a somewhat later stage, judging by the development of 
